ES2563803T3 - Internal bushing for transferring molten metal contained in a container, system for fixing said bushing and casting device - Google Patents

Abstract

Tube exchange device (10) for holding and replacing an exchangeable pouring spout to cast molten metal out of a container, said tube exchange device comprising a frame with a casting opening, said frame being suitable for fastening to the side bottom of a metal casting container and comprising a first upper part and a second lower part that are joined in a plane of intermediate section defining the plane in which an internal bushing (12) and an interchangeable pouring bushing form a sliding contact, the upper part of the frame comprising: a) means for receiving and fixing (50a, 50b, 50c) in place in their pouring position a bearing surface of an internal bushing (12) against a support part of the upper side part of the frame, such that the through hole of the inner hub (12) is in fluid communication with the casting opening, and the lower side part of the base tidor comprising, b) a passage extending along a first first direction axis (X) between an inlet opening and an outlet opening suitable for receiving and moving an interchangeable spout bucket from said inlet to said outlet , passing through a casting position aligned with the casting opening of the frame, c) means for moving and means (16) for guiding said interchangeable pouring bucket from a waiting position to a casting position aligned with the casting opening of the frame, and optionally to guide it to the exit, said guide means (16) running substantially parallel to the first direction (X), d) pressure means (18) aligned with the guide means and extending so substantially parallel to the first direction (X) at the level of the pouring position of the pouring spout to press up said interchangeable pouring spout in its casting position in the direction of the upper part rior of the frame, characterized in that the fixing means comprise three fixing elements (50a, 50b, 50c), in which the respective centroids of the orthogonal projections on the intermediate section plane of the fixing elements in their fixed position form the vertices of a triangle and why the fixing means (50a, 50b, 50c) are arranged transversely to said first direction (X).

Description

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Internal bushing for transferring molten metal contained in a container, system for fixing said bushing and casting device

TECHNICAL FIELD

The present invention relates to the technique of continuous casting of molten metal. More specifically, it refers to the fixation of an internal diver in a continuous casting installation.

BACKGROUND OF THE INVENTION

In a casting installation, the molten metal is generally contained in a metallurgical container, for example a casting trough, before being transferred to another tank, for example to a casting mold. The metal is transferred from the vessel to the vessel through a bucket system provided at the base of the metallurgical vessel, which comprises an internal hub located at least partially in the metallurgical vessel and which is placed in tight contact with a sliding transfer plate (or casting plate) located below and outside the metallurgical vessel and is aligned with the internal hub by means of a device for holding and replacing plates, mounted under the metallurgical vessel. This sliding plate can be a calibrated plate, a casting tube or a pot comprising two or more plates. Since all these types of plates are part of a hub comprising a plate connected to a tubular section of variable length depending on the applications and to distinguish them from the valve gates used, for example, in a spoon, they will be referred to in what it follows as "sliding bucket", "pour buza", "interchangeable dump bus" or combinations thereof. The pouring spout can be used to transfer molten metal in the form of either a free flow with a short tube, or a guided flow with a longer, partially submerged casting tube.

An example of such a casting facility is described in EP1289696. In order to provide the tight contact between the inner hub and the sliding spout hub, the device for holding and replacing tubes comprises fixing means, intended to press against the inner hub, particularly downwards, and pushing means, intended to press on the sliding plate of the spout bucket, particularly upwards, so that it presses the inner spout and the spout bucket against each other. These fixing and pressure means are generally arranged along the longitudinal edges of the inner hub and the sliding plate, the longitudinal direction corresponding to the plate replacement direction.

DE 94 08 700 U1 documents disclose a tube exchange device comprising an internal hub and an exchangeable spout bushing. The pouring bushing is replaced along a linear exchange direction; The pressure means for pressing the hub up against the inner bush are aligned with the direction of exchange. The fixing means for fixing the internal hub are complementary to the pressure means, as can be seen in Figure 3.

Document CN 201201049Y refers to an internal hub comprising cavities for receiving fasteners. The position of the fasteners with respect to the direction of sliding of the spout hub is not described.

Document DE20 2005 017 531 U1 refers to a sliding gate valve comprising refractory plates fixed in a frame.

US 5 044 533 refers to an internal hub for use in a tube exchange device. The internal hub comprises a tapered surface in correspondence with an annular fixing ring.

A difficulty is found in the fact that the tightness of the internal hub / sliding plate interfacial zone must be as perfect as possible, otherwise molten metal can flow between the two parts, damaging the surfaces of the refractory elements when replacing the Pouring diver with a new one. In addition, the absence of tightness (contact between the two refractory elements) allows air to infiltrate, which is harmful to both the refractory elements and the quality of the molten metal.

The present invention aims to improve the tightness of the contact surfaces between the internal hub plate and the sliding plate of the pouring hub. The present invention also aims to optimize the distribution of tensions in refractory elements to increase their useful life.

SUMMARY OF THE INVENTION

The present invention is defined in the attached dependent claims. Preferred embodiments are defined in the dependent claims. In particular, the present invention relates to a tube exchange device for holding and replacing an exchangeable spout bucket for casting molten metal from a container, said tube exchange device comprising a frame with a casting opening, being

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said frame suitable for fixing to the lower side of a metal casting container and comprising a first upper part and a second lower part, which are joined in an intermediate section plane defining the plane in which an internal diver and a Interchangeable pouring hub forms a sliding contact, comprising the upper side part of the frame:

a) means for receiving and securing in place in its pouring position a bearing surface of an internal bushing against a support part of the upper side part of the frame, such that the through hole of the internal bushing is in fluid communication with the casting opening, and the lower side part of the frame comprising,

b) a passage extending along a first first direction axis (X) between an inlet opening and an outlet opening suitable for receiving and moving an interchangeable spout hub from said inlet to said outlet, passing through a casting position aligned with the casting opening of the frame,

c) means for moving and means for guiding said interchangeable pouring bucket from a waiting position to a casting position aligned with the casting opening of the frame, and optionally to guide it to the exit, said guiding means running substantially parallel to the first address (X),

d) means aligned with the guiding means and extending substantially parallel to the first direction (X) at the level of the pouring spout of the pouring hub to press up said interchangeable pouring spout in its casting position in the direction of the upper part of the frame,

characterized in that the fixing means comprise three fixing elements, in which the respective centroids of the orthogonal projections on the intermediate section plane of the fixing elements in the fixing position form the vertices of a triangle and why the means They are arranged transversely to said first direction (X).

In a preferred embodiment, the fixing means comprise at least a first fixing element (50a) that intercepts and is arranged substantially normal to said first direction (X).

As will be commonly accepted by the person skilled in the art, the centroid of a flat figure is the point of intersection of all straight lines that divide said figure into two parts of the same moment around the line. In a triangle, the centroid is defined as the point of intersection of the medians. In particular, the triangle

formed by the centroids of the projections of the fixing means is defined by one or any combination of

any of the following geometries:

a) a first altitude of the triangle, called as altitude X, which passes through a first vertex, called as vertex X, is substantially parallel to the first direction (X)

b) a first median of the triangle called a median X, which passes through a first vertex, called a vertex X, is substantially parallel to the first direction (X)

c) a triangle according to a) or b) in which the vertex X points in the direction of the inlet opening;

d) a triangle according to a) or b) in which the vertex X points in the direction of the outlet opening;

e) all angles of the triangle are acute;

f) the triangle is isosceles, preferably according to a) and b), more preferably according to a), b), such that the vertex X is the meeting point of the two sides of equal length, more preferably of agree with

a), b), and e);

g) a triangle according to f) in which the angle, 2a, formed by the centroid (46) of the casting opening and the two vertices of the triangle other than the vertex X is between 60 and 90 °;

h) a triangle in which the angle formed by the vertex X is less than 60 °.

It is preferred that a first fixing element corresponding to the vertex X covers an angular sector, and, between 14 and 52 °, and the other two fixing elements (50b, 50c) cover an angular sector, p, between 10 and 20 °, all angles measured with respect to the centroid of the casting opening. It is further preferred that the internal flange (that is, adjacent to the casting cavity) of the projection of said first fixing element intercept the first axis (X) with a normal tangent to it. Still in a preferred embodiment, said first fixing element that extends normally to the first direction (X) is movably mounted between an inactive position and a fixing position, actuated from one position to the other by means of crankshaft drive.

In a preferred embodiment, the tube exchange device of the present invention comprises at least one gas connection to a gas source, said connection being arranged between two of the three elements of

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fixing, and preferably pointing substantially parallel to the first direction (X).

The present invention also relates to an internal hub made of a refractory core material for casting molten metal from a metallurgical vessel, and suitable for mounting on the top of a pouring tube exchange device, said inner hub comprising:

a) a substantially tubular part with an axial through hole fluidly connecting an inlet opening with an outlet opening, and

b) a plate comprising a first contact surface perpendicular to the axial through hole and comprising the outlet opening, and a second surface opposite the first contact surface that joins the wall of the tubular part with the side edges that define the plate perfometer and thickness, characterized in that the internal hub plate comprises three separate support elements protruding from the side edges, each comprising a support shoulder oriented in the direction of the contact surface and distributed around the flowmeter of the plate, in which the centroids of the orthogonal projections on a plane parallel to the contact surface of the supporting projections form the vertices of a triangle.

In a preferred embodiment, the triangle formed by the centroids of the projections of the three supporting projections is defined by one or any combination of any of the following geometries:

a) a first altitude of the triangle, called as altitude X, which passes through a first vertex, called as vertex X, is substantially parallel to the first direction (X)

b) a first median of the triangle, called median X, which passes through the vertex X, is substantially parallel to said first axis (X)

c) a triangle such that either the altitude X or the median X intercepts the center axis (Z) of the hub through the through hole in the center (46) of the through hole,

d) all angles of the triangle are acute;

e) the triangle is isosceles, preferably according to a) and b), more preferably according to a), b), and c) such that the vertex X is the meeting point of the two sides of equal length, plus preferably according to a), b), and d);

f) a triangle according to c) in which the angle, 2a, formed by the center of the through hole and the two vertices of the triangle other than the vertex X is between 60 and 90 °;

g) a triangle in which the angle formed by the vertex X is less than 60 °.

All contact surfaces of the inner hub plate except the first one are preferably at least partially covered with a metal cover, the three supporting projections being part of said metal cover. In a preferred embodiment, the internal bushing comprises means of connecting gas in fluid communication with the through hole of the internal bushing, so that the molten metal flowing through the internal bushing can be covered by a blanket of inert gas, such as Ar, He, Ne and the like. The gas connection means can also be in fluid communication with a groove that is located on the contact surface 26 of the inner hub, in order to protect the metal melt from oxidation in the event of a leak in the interfacial zone between the contact surface of the internal bushing and the sliding surface of the pouring bushing. The gas connection means are preferably arranged between two supporting projections.

The present invention also relates to a set of a tube exchange device as defined above and of an internal hub, in which the inner hub comprises supporting elements that correspond to the fixing means of the tube exchange device. . Preferably, the inner diver is also as defined above.

The present invention also relates to a metal cover for coating an internal bushing as defined above, said metal cover comprising a main surface with an opening for housing the tubular part of the bushing and lateral edges extending from the surface perfometer. main, characterized in that said metal cover comprises three separate support elements protruding from said lateral edges, each support element comprising a support shoulder that is oriented away from said main surface and disposed around the periphery of the metal cover such that the centroids of each of said three supporting elements form the vertices of a triangle. The word centroid means in this case the geometric center of the object's shape. The various geometries of the internal bucket support protrusions defined above apply mutatis mutandis to the present metal shell since the protrusions are part of the metal shell.

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The invention will be more clearly understood by reading the following description, offered merely by way of non-limiting example of the scope of the invention, with reference to the figures, in which:

Figure 1a is a perspective view of an internal diver according to an embodiment, in its casting orientation;

Figure 1b is a perspective view of the diver of Figure 1a when turned upside down in the vertical direction;

Figure 2 is a top view of the hub of Figure 1 fixed in place in a tube exchange device according to the present invention;

Figure 2a is a sectional view illustrating the structure of a fixing element of Figure 2; Figures 3 and 3a are top views of the diver of Figure 1; Figure 4 is a sectional view of a fixing element;

Figure 5 is a sectional side view of the inner hub of Figure 1 placed in its casting position in the tube exchange device before being fixed; Y

Figures 5a to 5d are sectional views along a longitudinal plane illustrating the fixing steps of the fixing means in Figure 4 for fixing a bearing shoulder of an internal hub;

Figures 6a-c show the distribution of compression stresses around the casting channel for various distributions of the fixing means of the internal hub.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a tube exchange device for holding and replacing a sliding bushing mounted under a metallurgical container for casting molten metal contained in the container, and for guiding the sliding bushing to a casting position in which it extends from a casting channel of an internal hub arranged in the metallurgical vessel. The plate replacement direction corresponds to a longitudinal direction of the device, and the directions not parallel to said longitudinal direction correspond to transverse directions of the device, with the direction perpendicular to the longitudinal direction referred to as the normal direction. The sliding plate of the pouring bushing and the internal bushing each have two substantially longitudinal edges and two generally normal transverse edges.

The present invention proposes to apply the fixing force along the transverse edges of the inner hub, while applying the force of pressure on the longitudinal edges of the spout hub, so that the sealing at the transverse edges is improved of the contact plane of the internal hub / sliding plate. In other words, due to the fixing means and the pushing means arranged in this way, it is possible to apply a force that establishes the contact substantially over the entire circumference of the contact plane of the internal / sliding bushing, hence a superior tightness and therefore a longer useful life of the pieces and an improved quality of the molten metal. In particular, the inventors appreciated that it is more advantageous to apply the forces in this way than when applying the pushing force and the fixing force in opposition, as in the prior art, since the greater pressure on the longitudinal edges of the internal hub and the sliding plate can bend and separate the respective transverse edges.

In addition, the fixing means located in the transverse direction can further contribute to further reference the internal hub in relation to the frame of the tube exchange device along the longitudinal direction, which is particularly advantageous. In fact, the internal bushing is subjected to substantial shear forces in the longitudinal direction during the plate the replacement of a pouring bushing, and the fixing forces distributed in the transverse direction contribute to improving the stability of the internal bushing in the direction longitudinally, and thus blocking said hub in the longitudinal direction despite the movements of the shear stresses due to plate replacements.

The term "fixing means" refers to means rotatably mounted on the frame of the tube exchange device to apply a fixing force on a fixing surface of an internal hub, said force being transmitted to an opposite bearing surface against a complementary support surface of the frame of the tube exchange device. Generally, the force applied by the fixing means on the inner bushing is a downwardly directed force applied on an upper surface of the inner bushing, and the force applied by the pressing means on the sliding bushing plate opposes the anterior and is generally oriented upwards, applied on the lower surface of the plate. The vertical direction is defined as the flow direction of the molten metal at the outlet of the metallurgical vessel. The cross direction is defined as any direction

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secant to the longitudinal direction, and the normal direction is perpendicular to both the longitudinal and vertical directions, such that the longitudinal, normal and vertical directions define an orthogonal reference system. In addition, it should be appreciated that the forward direction is defined with reference to the replacement direction of the diver in the tube exchange device, the plate moving from the back to the front to adopt the following successive positions: standby position (when another diver is already in the casting position), casting position (when the hole of the pouring diver is aligned with the through hole of the internal diver), sealing position (when a sealing surface arranged on the plate of the diver The outlet of the through hole of the internal hub is oriented and sealed and the ejection position (when the sliding face of the plate is released from the tube exchange device). It should also be noted that various refractory surfaces of the plates of both the internal and the spout are generally coated with a metal cover. The pouring hub generally comprises a tubular extension of varying lengths depending on the applications. The tubular extension can be extended sufficiently so that the end thereof is immersed in the downstream metallurgical container, for example in continuous casting molds. The casting tube to be submerged is made of a refractory element.

In the following, the substantially vertical direction corresponding to the casting direction is referred to as the Z direction, and the central axis of the through hole of the internal hub as the Z axis, which is parallel to the Z direction when the diver internal is mounted in its casting position in the tube exchange device. The longitudinal direction, which corresponds to the plate replacement direction, is referred to as the X direction, which is substantially normal to the Z direction; The X axis is parallel to the X direction and passes through the centroid of the casting opening of the tube exchange device.

The present invention is based on the observation that in traditional tube exchange devices, as disclosed, for example, in EP1289696, in which the fixing means for holding the inner tube at the top of the frame are located mode substantially parallel to the direction X, and substantially on the pressure means 18 that press the spout bushing upward against the contact surface of the inner bushing 12 give problems of tightness. The inventor carried out a stress distribution analysis around the casting opening and concluded that the level of compression tension in the transverse part of the plates was much lower than in the longitudinal sides, resulting in the possible formation of a thin, but unacceptable, hole that could lead to leaks of molten metal (see Figure 6a). The solution proposed in the present invention to solve this problem is to locate at least three fixing elements 20 transverse to the X direction along which the pressure means 18 are aligned. This apparently simple solution unexpectedly solves the problem of the risk of leaks of the tube exchange systems of the prior art, as will be seen below.

In a continuous casting installation of molten metal, such as for casting molten steel, a device 10 is used to hold and replace sliding bushes for the transfer of the metal contained in a metallurgical container, for example a casting trough, to a tank , such as one or a plurality of casting molds. The device 10, partially represented in Figure 2, is mounted under the metallurgical container, aligned with an opening in the floor thereof, such as to insert through it an internal hub 12, fixed to the frame of an exchange device of tubes 10 and attached to the base of the metallurgical vessel, for example with cement. A side view representation of a typical tube exchange device can be found in Figure 1 of EP1289696. The through hole 14 of the internal hub 12 defines a casting channel and the device 10 is arranged so that it can guide the sliding plate of a pouring hub to a casting position, such that the axial hole of the latter is placed in fluid communication with the through hole 14 of the inner hub. For this purpose, the device 10 comprises means 16 for guiding the slider through an inlet and from a waiting position to a casting position. For example, the guide means may be in the form of guide rails 16. The rails 16 are arranged along the longitudinal edges 17a, 17b of the channel of the device 10 leading from the entrance of the device to the inactive position and up to the casting position. Also, in the pouring position of the pouring bushing, the device 10 comprises means 18 arranged parallel to the direction X to press the pouring bushing plate against the contact surface of the inner bushing 12, for example compressed springs 18 , said means being arranged to apply a force on a lower surface of each of the two longitudinal edges of the slide plate of the pouring hub, so that it presses the plate in a tight contact against the contact surface of the inner hub 12 and therefore to create a fluid tight connection between the through hole 14 of the inner hub and the axial hole of the spout hub. As can be seen in Figure 2, the springs 18 are distributed along the longitudinal edges 17a, 17b of the device 10 in a manner substantially parallel to the direction X. The device 10 also comprises means 20 for fixing the internal hub, described in more detail below, and arranged to apply a force on an upper surface of two transverse edges of the inner hub 12, so as to keep the inner shaft pressed against the device 10. The term transverse means in the present context not parallel to , or secant with, address X.

The internal bushing 12 comprises a metal cover 22, which covers everything but the first contact surface (26) of the plate 24 of the internal bushing made of a refractory material, as can be seen in Figure 1b. The

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Metal cover 22 reinforces the refractory element 24 and is preferably attached to the plate using a cement. The refractory plate is essential to withstand the high temperatures whenever the diver makes contact with the molten metal, but its mechanical properties, in particular compression, shear, friction and wear resistance are insufficient whenever there is a stress concentration. For this reason, the refractory plate is coated with a metal cover whenever mechanical tensions are applied but far from any possible contact with molten metal. The thickness of the metal cover can vary between approximately 1 mm to more than 6 mm, the walls being thicker generally when the metal cover is made of cast iron. The metal cover is separated from the contact surface 26 of the inner bushing (see Figure 1b) when the latter is brought into intimate contact with the sliding surface of the plate of a pour bus. No metal could be used to cover the contact surface as it would be damaged in case of any leakage of molten metal, with dramatic consequences. As mentioned above, the contact surface 26 of the inner bushing is intended to be placed in tight contact with the sliding surface of a pouring bushing when said bushing is pushed into position by the device 10 to the casting position, this it is, oriented towards the inner bushing 12. One end of the through hole 14 of the inner bushing opens on the contact surface 26.

The internal hub 12 comprises three separate support elements 30a, 30b, 30c that protrude from the side edges and are distributed around the plate perfometer. Each support element comprises a support projection (34a, 34b, 34c) oriented in the direction of the contact surface 26. The centroids of the orthogonal projection of the respective projections on a plane parallel to the contact surface 26 form the vertices of a triangle. The support elements and the projections thereof are really part of the lining pieces of the metal cover of the inner hub plate. This is advantageous since the fixing force is applied to a metal surface that does not crack as it would probably occur with a refractory when exposed to high concentrations of compressive tension and shear. The surfaces of the three highlights define the support surface. These are preferably coplanar, although this is not essential for the present invention. Preferably they are parallel to the contact surface 26 although this is also not essential, since a slight inclination of the projections can help center the internal hub on the tube exchange device 10. However, it is clear that the support projections of the internal bushing must be complementary to the support part and fixing means 20 of the tube exchange device 10. In opposition to the support projections (34a, 34b, 34c), the internal bushing comprises fixing surfaces (32a, 32b , 32c) which are suitable for receiving the fixing means of the tube exchange device, in such a way that they fix in their position the support rims of the internal hub against complementary support parts of the frame of the tube exchange device. The fixing surfaces are preferably metal and may be part of the second surface of the plate, opposite the contact surface or may be part of the support elements although separated from said second surface, as illustrated in Figure 1.

The support elements 30a, 30b, 30c are separated and projected from a peripheral surface 36 of the inner hub plate 12, said surface 36 extending from the bottom contact surface 26 of the plate, preferably although not necessarily in a Z direction substantially vertical In one embodiment, a refractory material can be extended between the support shoulder and the fixing surface of a support element of the internal hub. In this embodiment, a part of the refractory is exposed to the compression stresses of the fixing means 20, but any tension concentration is distributed by the metal layer that separates the refractory from the fixing means and supporting surfaces of the device of tube exchange. In a preferred embodiment, the supporting shoulder and the opposite fixing surfaces are separated only by metal. This guarantees that the fixing force is not applied at all to the refractory, but only to the metal. As in the example illustrated in the figures, the three support elements 30a, 30b, 30c are made entirely of metal, that is, there is only metal between the support projections 34a, 34b, 34c and the fixing surfaces 32a , 32b, 32c.

As can be seen in FIG. 3, the inner hub 12 has two opposite edges 40a, 40b, substantially longitudinal, and two opposite edges 42a, 42b substantially normal to the longitudinal edges. In addition, a vertical central longitudinal plane P can be defined by the X and Z axes and the three support elements 30a, 30b, 30c can be arranged in a Y-shape at the periphery 36 of the hub 12, the base 44a of the And in the central longitudinal plane P coaxially with the X axis and the two arms 44b, 44c of the Y being disposed on each side of said plane P and all the arms of the Y is located in the centroid 46 of the through hole 14 of the hub internal More specifically, the second 30b and third 30c support elements have second 34b and third 34c support projections, each of these second 34b and third 34c support projections being disposed on each side of the longitudinal plane P. In the described example, the Second and third support highlights are arranged symmetrically, although this is not necessary. In addition, each of the orthogonal projections of the three support projections 34b, 34c on a plane parallel to the contact surface 26 has a centroid 34'b, 34'c located at an angle a (alpha) between 30 and 45 ° in relation to the longitudinal plane P, with centroid reference 46 of the internal hub 12, which corresponds to the center of the casting hole 28. In addition, each of the second supporting projections 34b and third 34c is included in an angular sector p (beta ) between 10 and 20 ° with reference to the center 46 of the internal hub 12. In addition, the first support member 30a has first support projections 34a that pass through the longitudinal plane of the hub 12. More specifically, the edge of support 34a extends substantially symmetrically in relation to the plane P,

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the centroid 34'a of this surface being located in the plane P. The supporting shoulder 34a can be extended on a surface included in an angulary (gamma) sector between 14 and 52 ° with reference to the center 46 of the inner hub. In the case represented in Figure 3, the centroids 34'a, 34'b, 34'c of the projection of the supporting projections correspond to the centroids of the projection of the fixing surfaces 32'a, 32'b, 32'c.

The internal hub 12 may further comprise gas connection means 48, in fluid communication with the central hole 14 of the inner hub and / or with a groove that is located on the contact surface 26. It is preferred that said means 48 be arranged between the second 30b and third 30c support elements. In this case, the means 48 comprise one or two channels that open on a transverse vertical surface or transverse edge 49 that belongs to the peripheral surface 36 and that connect the two supporting elements 30b, 30c. The injected gas is, for example, argon.

The fixing means 20 of the tube exchange device comprise three fixing elements 50a, 50b, 50c arranged transversely to the X axis. The three fixing elements 50a, 50b, 50c are arranged in a Y-shape at the periphery of the internal hub 12 (see Figure 2), that is, a first fixing element 50a at the base of the Y, arranged at the rear of the central longitudinal plane P and second 50b and third 50c fixing elements at the ends of both arms of the Y, arranged on each side of the front part of said plane P. As can be seen, the fixing means are arranged to apply the force thereof on the transverse edges 42a, 42b of the inner hub. The fixing elements 50a, 50b, 50c have a complementary configuration of the support elements 30a, 30b, 30c. Thus, the first 50a, second 50b and third 50c fixing elements respectively apply a fixing force on the first 34a, second 34b and third 34c bearing projections described above.

The second and third fixing elements 50b, 50c can be substantially identical. Thus, only the structure of element 50b will be described with reference to Figures 2 and 2a. The fixing element 50b is rotatably mounted on an axis 52b attached to the frame 31, which extends substantially in a transverse direction. The element 50b has a free end that supports a so-called fixing surface 54b, intended to come into contact with the fixing surface 32b of the support element 30b, and to apply a fixing force on said surface 32b by pressing on it. For this purpose, the element 50b is actuated by a rotating device 56b (which pivots around a vertical axis) that acts as a cam in contact with the element 50b. More specifically, when the cam 56 rotates, it applies a horizontal force on the free end of the element 50b, in accordance with the arrow illustrated in Figure 2a, which pivots the free end down, and thus the surface 54b around the axis 52b The downward rotation of the surface 54b thus generates a fixing force on the surface 32b that is transmitted to the opposite bearing shoulder 34b that is fixed in its position against the corresponding support part of the frame. It should be appreciated that the fixing element 50b not only applies a downward fixing force, but also a horizontal force, intended to block the shoulder 34b horizontally. Other fixing mechanisms known to those skilled in the art can be used within the scope of the present invention, since it is the orientation rather than the fixing means of the fixing means that defines the essence of the present invention.

Next, the structure of a first fixing element 50a will be described with reference to Figures 4, 5 and 5a to 5d. The first fixing element 50a has a shape similar to that of the element 50b shown in Figure 2a, except that it can be extended over a surface larger than the element 50b. The element 50a is rotatably mounted on an axis 52a attached to the frame 31, which extends in a direction transverse to the direction X and has a free end that supports a fixing surface 54a, intended to come into contact with the surface of 32a fixing by pressure on it. The element 50a can be operated differently from the element 50b, particularly by means acting as a connecting rod. More specifically, it is driven by a rotating device 56a pivotally mounted around an axis in the normal example to the X axis and acting as a cam in contact with a cylinder 58. The cylinder 58 can be moved by translation in the X direction. This supports a rod 60 that acts as a connecting rod, one of whose ends 62 is rotatably mounted around the free end of the fixing elements 58 and the opposite end 64 of which is rotatably mounted around the free end of the element of fixation 50a, the element 50a acting as a connecting rod. In addition, the cylinder 58 forms a housing for a bar 66 returned by return means 68 of the fixing element 50a in the inactive position, for example a compressed spring.

The fixing element 50a is movably mounted between an inactive position and a fixing position, actuated by the connecting rod system, as follows. The inactive position is illustrated in Figure 5a. To move to the fixing position, it is necessary to rotate the mobile device 56a around the axis thereof, so that it moves the cylinder 58 in the horizontal direction illustrated by arrow 70. As a result of this translation, the connecting rod 60 rotates the element 50a around the axis 52a thereof, as illustrated in Figures 5b, 5c and 5d, such that the fixing surface 54a of the fixing element presses on the fixing surface 32a of the support element and the fixing element 50th adopts the fixation position of it. Simultaneously with the translation of the cylinder 58, the bar 66 rests against the vertical wall of the support element 30a, which compresses the spring 68 as illustrated in Figure 5c and 5d. By compressing this spring, the system can return to the inactive position simply by turning the

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device acting as a cam 56a. In fact, in such a crankshaft system, when the element 50a is in the fixing position, as illustrated in Figure 5d, the rotation of the device 56a allows the cylinder 58 to move by translation in the direction indicated by the arrow 72 under the action of the spring 68 that is released, and thus allows the fixing element to return to the position illustrated in Figure 5a.

The device 10 illustrated in the attached figures also comprises, between the two fixing elements 50b, 50c two gas injection channels for the bucket 12, which open on a vertical transverse surface 51 of the device 10. Thus, when the element 50a is in the fixation position, the injection channels of the device 10 extend from the channels 48 of the hub 12, and the fixation positions of the elements 50b, 50c provide a particularly tight connection of said channels.

The procedure for fixing the internal bushing 12 in the device 10 will be described below based on the embodiment illustrated in the figures. At the beginning of the fixing procedure, the internal bushing 12 is simply placed on the frame 31 of the tube exchange device 10. The fixing procedure comprises a first stage of supporting the transverse vertical surface 49 of the bushing 12, arranged between the elements of support 30b, 30c against the transverse vertical surface 51 of the frame 31 of the device 10, followed by the actuation of the first fixing element 50a in the fixing position. The first element 50a thus moves by translation in accordance with the arrow 70 in Figure 5a, rests against the support element 30a, which presses the inner hub 12 against the leading transverse edge 51 of the device 10, thereby referencing it very precise against said leading edge. It is understood that the establishment of the fixing position by the fixing element 50a simultaneously results in the compression of the joints arranged in the gas injection channels 48. The joints may be located in the internal hub or in the device. These are preferably made of graphite. The translation along the arrow 70 allows controlled compression. Once the fixing element 50a is in the fixing position, the assembly procedure is followed by the optionally simultaneous actuation of the two fixing elements 50b, 50c in the fixing position. The fixing of the first element 50a followed, in a second stage, by the fixing of the other two elements 50b, 50c allows a particularly simple procedure, all fixing elements 50a, 50b, 50c and the actuation means thereof forming a particularly advantageous fixing system.

Among the benefits of the internal hub 12 and the tube exchange device 10 described above, it should be appreciated that the fixing means apply the force thereof on the transverse edges 42a, 42b of the inner hub, while the means of pressure 18 applies their force on the longitudinal edges of the sliding spout plate against the longitudinal edges 17a, 17b of the device 10. As a result, a pressure is applied substantially over the entire circumference of the contact surface between the internal hub 12 and the sliding plate, hence the upper seal (see Figure 6 (c)).

Another advantage of the present invention is that, after the use of the internal hub 12, the same metal cover 22 can be used again to coat a new refractory element 24.

The present invention clearly improves the fluid tightness of the interfacial zone between the contact surface 26 of an internal bushing and the sliding surface of the plate of a pouring bushing in a tube exchange device 10. Figure 6 shows the distribution of compression tension calculated as a result of the arrangement of the fixing means around the periphery of the casting opening: the darker the color, the greater the compression tension. A configuration of the prior art is shown in Figure 6 (a) as described, for example, in document EP1289696 with the fixing means 20 for fixing in place the internal bushing arranged along the longitudinal edges , parallel to the X axis and resting substantially on the pressure means 18 to press the sliding surface of the pouring bushing against the contact surface 26 of the inner bushing. It can be seen that the pressure is high only in the part adjacent to the longitudinal edges, with a low pressure along the transverse direction, which results in a high risk of leaks of molten metal when casting and an air intake significant. Figures 6 (b) and (c) on the other hand are in accordance with the present invention.

In Figure 6 (b) there are two fixing elements 20 for fixing the internal hub, which are substantially normal to the X axis. It can be seen that the part of the plate comprising the X axis is exposed to a higher level of pressure than in the previous geometry of figure 6 (a). In Fig. 6 (c) three fixings are arranged around the internal hub perfometer, in which the centroids of the perpendicular projections of each fixing means 20 in their fixing positions on the plane of the contact surface of the diver internal form the vertices of a triangle, or the arms of a "Y" that join in the centroid 46 of the through hole of the internal diver, as discussed above. It can be seen in Figure 6 (c) that the level of compression is very homogeneous with the entire plate perfometer exposed to high pressure, thus guaranteeing the fluid tightness of the interfacial zone between the two surfaces of the internal hub and the spill diver. Since the three fixation system seems to be so efficient, various modes of realization of three fixation systems are discussed.

An altitude of a triangle is a straight line through a vertex and perpendicular to the opposite side. The intersection of the altitudes is the orthocenter. A median of a triangle is a straight line through a vertex and the midpoint of the

5

10

fifteen

twenty

25

30

35

40

opposite side, and divide the triangle into two equal areas. The point of intersection of the medians of a triangle is called centroid.

In one embodiment, it is preferred that a median, referred to as the median X and / or an altitude called the altitude X, both passing through the vertex X of the projected triangle is coaxial with the X axis, as shown in the figures 2 (a) and 6 (c). The other two fixing means 20 are arranged on both sides of the X axis. Preferably, the triangle is isosceles with the two sides of equal length joining at the X vertex, as shown in the previous figures.

The vertex X can point in the direction of the inlet opening. This configuration is advantageous in the case of a gas connection located between the second and third vertices, instead of the X vertex, since the friction applied in the longitudinal direction by a spout hub that is being inserted, respectively extracts the part The bottom of the tube exchange device would push the inner bushing against said connection, thus ensuring a tight connection. In addition, the friction forces cooperate with the crankshaft system installed in the first fixing means as explained above. Alternatively, the vertex X may be pointing towards the outlet opening.

It is preferred that all angles of the triangle are acute to ensure a homogeneous distribution of the fixing means around the periphery of the diver. In particular, it is preferred that the vertex X be less than 60 °. The angle 2a, on the other hand, formed by the centroid (46) of the casting opening and the two vertices of the triangle other than the vertex X is preferably between 60 and 90 °.

As illustrated in the figures, it is preferred that the triangle be isosceles, preferably with the median X coaxial with the X axis. More preferably, the vertex X should be the point of intersection of the two sides of equal length (with this configuration, the median X and the altitude X are coaxial).

 10

 tube exchange device

 12

 internal diver

 14

 through hole of the inner hub

 16

 gufa means

 17a, 17b

 longitudinal edges of the device

 18

 pressure means

 twenty

 fixing means

 22

 metal cover

 24

 refractory element

 26

 contact surface

 28

 laundry opening

 30a, 30b, 30c

 support elements

 31

 frame

 32a, 32b, 32c

 fixing surface of the support elements

 34a, 34b, 34c

 support highlight of support elements;

 36

 peripheral surface

 40a, 40b

 longitudinal edges of the diver;

 42a, 42b

 transverse edges of the diver

 44th

 Y base

 44b, 44c

 arms of the Y

 46

 centroid of the opening of the through hole of the inner hub

 48

 gas injection means

 49

 transverse surface of the diver

 50a, 50b, 50c

 fasteners

 51

 transverse surface of the device

 5 52a, 52b

 axis of the fixing element

 54b

 fixing surface of the fixing element

 56a, 56b, 56c

 rotating device or cam

 58

 cylinder

 60

 rod that acts as a connecting rod

 10 66

 bar

 68

 return means

 70

 horizontal direction

 72

 opposite direction of address 70

Claims (15)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. Tube exchange device (10) for holding and replacing an exchangeable pouring spout to cast molten metal out of a container, said tube exchange device comprising a frame with a casting opening, said frame being suitable for clamping to the lower side of a metal casting vessel and comprising a first upper part and a second lower part that are joined in an intermediate section plane that defines the plane in which an internal diver (12) and an exchangeable discharge hub they form a sliding contact, comprising the part of the upper side of the frame: a) means for receiving and fixing (50a, 50b, 50c) in place in their pouring position a bearing surface of an internal hub (12) against a support part of the upper side part of the frame, such that the through hole of the inner hub (12) is in fluid communication with the casting opening, and the lower side part of the frame comprising, b) a passage extending along a first first direction axis (X) between an inlet opening and an outlet opening suitable for receiving and moving an interchangeable spout hub from said inlet to said outlet, passing through a casting position aligned with the casting opening of the frame, c) means for moving and means (16) for guiding said interchangeable spout bus from a waiting position to a casting position aligned with the casting opening of the frame, and optionally for guiding it to the exit, said guide means ( 16) substantially parallel to the first address (X), d) pressure means (18) aligned with the guiding means and extending substantially parallel to the first direction (X) at the level of the casting position of the pouring spout to press up said interchangeable pouring spout in its casting position in the direction of the upper part of the frame, characterized in that the fixing means comprise three fixing elements (50a, 50b, 50c), in which the respective centroids of the orthogonal projections on the intermediate section plane of the fixing elements in their fixed position form the vertices of a triangle and why the fixing means (50a, 50b, 50c) are arranged transversely to said first direction (X). 2. Tube exchange device according to one of the preceding claim, wherein the fixing means comprise at least one first fixing element (50a) that intercepts and is arranged substantially normal to said first first direction axis (X) . 3. Tube exchange device according to any of the preceding claims, wherein the triangle formed by the centroids of the three fixing elements is defined by one or any combination of any of the following geometries: a) a first altitude of the triangle, referred to as altitude X, which passes through a first vertex, referred to as a vertex X, is substantially parallel to the first direction (X) b) a first median of the triangle called a median X, which passes through a first vertex, called a vertex X, is substantially parallel to the first direction (X) c) a triangle according to a) or b) in which the vertex X points in the direction of the inlet opening; d) a triangle according to a) or b) in which the vertex X points in the direction of the outlet opening; e) all angles of the triangle are acute; f) the triangle is isosceles, preferably according to a) and b), more preferably according to a), b), such that the vertex X is the meeting point of the two sides of equal length, more preferably of agree with a), b), and e); g) a triangle according to f) in which the angle, 2a, formed by the centroid (46) of the casting opening and the two vertices of the triangle other than the vertex X is between 60 and 90 °; h) a triangle in which the angle formed by the vertex X is less than 60 °. 4. Tube exchange device according to the preceding claim, wherein a first element of fixation (50a) corresponding to the vertex X covers an angular sector, and, between 14 and 52 °, and the other two fixing elements (50b, 50c) cover an angular sector, p, between 10 and 20 °, all the angles measured with respect to the centroid (46) of the casting opening. 5. Tube exchange device according to claim 3 (f), wherein the inner flange of the 5 10 fifteen twenty 25 30 35 40 Four. Five projection of said first fixing element, corresponding to the vertex X, intercepts the first axis (X) with a normal tangent to it. 6. Tube exchange device according to any one of claims 1 to 5, comprising at least one gas connection to a gas source, said connection being arranged between two of the three fixing elements (50b, 50c) and preferably pointing substantially parallel to the first direction (X). 7. Tube exchange device according to any one of claims 1 to 6, wherein the first fixing element (50a) extending normally to the first direction (X) is movably mounted between an inactive position and a fixing position, actuated from one position to the other by means of a crankshaft actuation means (60, 50a). 8. Internal bushing (12) made of a refractory core material for casting molten metal from a metallurgical container, and suitable for mounting on the top of a pouring tube exchange device, said internal bushing comprising: a) a substantially tubular part with an axial through hole fluidly connecting an inlet opening (14) with an outlet opening (28), and b) a plate comprising a first contact surface (26) normal to the axial through hole and comprising the outlet opening (28), and a second surface opposite the first contact surface (26) that joins the wall of the tubular part with the lateral edges (22, 36, 49) that define the perfometer and plate thickness, characterized in that the internal hub plate comprises three separate support elements (30a, 30b, 30c) that protrude from the side edges, each support element comprising a support shoulder (34a, 34b, 34c) oriented in the direction of the contact surface (26) and distributed around the plate perfometer, in which the centroids of the orthogonal projections on a plane parallel to the contact surface (26) of the supporting projections form the vertices of a triangle. 9. Internal hub (12) according to the preceding claim, wherein all but the first contact surface (26) of the inner hub plate are at least partially coated with a metal cover, and in which the three protrusions of support are part of said metal cover. 10. Internal hub (12) according to claim 8 or 9, in which the triangle formed by the centroids of the projections of the three supporting projections is defined by one or any combination of any of the following geometries: a) a first altitude of the triangle, called as altitude X, which passes through a first vertex, called as vertex X, is substantially parallel to the first direction (X) b) a first median of the triangle denominated as median X, which passes through the vertex X, is substantially parallel to said first axis (X) c) a triangle such that either the altitude X or the median X intercepts the center axis (Z) of the hub through the through hole in the center (46) of the through hole; d) all angles of the triangle are acute; e) the triangle is isosceles, preferably according to a) and b), more preferably according to a), b), and c) such that the vertex X is the meeting point of the two sides of equal length, plus preferably according to a), b), c) and d); f) a triangle according to c) in which the angle, 2a, formed by the center (46) of the through hole and the two vertices of the triangle other than the vertex X is between 60 and 90 °; g) a triangle in which the angle formed by the vertex X is less than 60 °. 11. Internal bushing (12) according to any one of claims 8 to 10, comprising gas connection means (48) in fluid communication with the through through hole (14) and / or with a groove that is located above the contact surface 26 of the inner bushing (12), said gas connection means being preferably arranged between two bearing projections (30b, 30c). 12. Assembly of an internal hub (12) and a tube exchange device (10) according to any one of claims 1 to 7, wherein the inner hub (26) comprises support elements (30a, 30b, 30c ) coinciding with the fixing means (50a, 50b, 50c) of the tube exchange device. 13. Assembly according to the preceding claim, wherein the inner hub is according to any of claims 8 to 11. 14. Metal cover (22) for coating an internal bushing (12) according to any of claims 9 to 11, depending on claim 9, said metal cover (22) comprising a main surface with a 5 opening to accommodate the tubular part of the hub and lateral edges extending from the perfometer of the main surface, characterized in that said metal cover comprises three separate support elements (30a, 30b, 30c) protruding outward from said edges lateral, each support element comprising a support shoulder (34a, 34b, 34c) that is oriented away from said main surface, and which are arranged around the periphery of the metal cover such that the centroids of each of said Three 10 supporting elements form the vertices of a triangle. 15. Metal cover (22) according to the preceding claim, in which the positions of the three supporting projections are as defined in claim 10 when the metal cover is coated on an internal bushing (12).